Grill frame structure



FIG. 1 is a perspective view of a grill frame structure embodying theinvention;

FIG. 2 is a second perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is right side view thereof;

FIG. 6 is a left side thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a rear view thereof.

The details shown in broken lines form no part of the claimed design.

The ornamental design for a grill frame structure, as shown anddescribed.